Description (shell):Shell brittle, roughly oblong, umbonesanterior to midline and incurved. Posteriorhinge line straight, posterior margin truncate; anteriorhinge line continuous with regularly convex anterior margin. Sculpture of closely spaced, small corrugated ridges and grooves, most pronounced close to posterior margin, often worn about umbones; fine radiating striations also present. Lunule and escutcheon shallow, indistinct. Three cardinal teeth in each valve, centre one in left, and centre and posterior in right, bifid. Adductor scars and pallial line distinct; pallial sinus deep, U-shaped, extending well beyond midline of shell, to a point below the anterior half of the ligament. Lower limb of pallial sinusposteriorly confluent with the pallial line.